CVE-2015-4200: Cisco IOS

High severity, CVSS 7.8. EPSS: 3.4% chance of exploitation in the next 30 days.

Memory leak in the IPv6-to-IPv4 functionality in Cisco IOS 15.3S in the Performance Routing Engine (PRE) module on UBR devices allows remote attackers to cause a denial of service (memory consumption) by triggering an error during CPE negotiation, aka Bug ID CSCug00885.

Affected products

• Cisco IOS: version 15.3(3)s only; version 15.3s only

Published 2015-06-23. Last modified 2026-06-17.